• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.6
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• pp.73-81
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• 2012

Concrete structures are commonly exposed to freezing-thawing condition. This freezing-thawing action changes the pore structure of concrete, and it can reduce the durability of concrete. In this study, the change of the internal pore structure and durability of concrete due to freezing-thawing action are investigated. According to results, the excellent durability records were reported by the existing evaluation methods for all mixes. However, the pores, 50~100nm size in diameter, are increased in concrete specimens exposed to freezing-thawing action, and the chloride penetration resistance was significantly reduced. The linear relationship between pore structure and chloride penetration resistance was shown in water cured concrete. Meanwhile, the linear relationship was decreased when concrete is exposed to freezing-thawing condition. It is desirable to review the criterion of durability evaluation for concrete specimens exposed to freezing-fthawing and chloride attack condition, simultaneously.

• Magazine of the Korea Concrete Institute
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• v.10 no.4
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• pp.205-212
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• 1998

Frost damage of a storage tank for chemical admixtures caused by a low temperature in winter and quality deterioration of chemical admixtures have been often reported. However, there have been few regulations and researches related to the frost damage of chemical admixtures and facilities. Therefore, this paper is intend to investigate not only, the freezing points of chemical admixtures such as AE admixtures and water-reducing AE admixtures, etc., but also the quality variation of concrete used with chemical admixtures before freezing and after freeze-thaw cycles. According to the results of experiments, most chemical admixtures except anti-freezing agent and accelerating water-reducing AE admixtures should be kept from being frozen in low winter temperatures. However, full agitation of frozen chemical admixtures dose not cause the problems of concrete related to the quality of chemical admixtures.

• Journal of Navigation and Port Research
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• v.37 no.2
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• pp.129-135
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• 2013

Recently, waste water treatment system is developed in small and middle size to get more economic advantage. Freeze concentration system has high thermodynamic efficiency and low energy consumption, can re-use purified water and cold energy obtained from ice. This study was experimentally performed to investigate pollution containment in frozen layer by cooling wall temperature, air-bubble flow methods, initial ice-lining thickness of frozen layer in NaCl aqueous solution and the representative heavy metals, Pb and Cr aqueous solution. As the result, a decrease in the cooling wall temperature bring a higher growth rate of ice front and the more solute was involved in frozen layer. The method to inject directly air-bubble into ice-liquid interface through ring shape nozzle gave high purity of ice compared to indirect method. Ice lining in 5mm thickness resulted in frozen layer with higher purity than 1mm thickness.

• Korean Journal of Animal Reproduction
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• v.23 no.2
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• pp.165-174
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• 1999

Boar semen can be frozen successfully. However, there is a large variability in the extent of damage boar semen samples experiences during cryopreservation. This experiment was undertaken to find out factors that affect a post-thaw viability of boar spermatozoa. For this purpose, cryodiluents(BF5, LEY, Soejima and M-Soejima), cryoprotectants(glycerol. ethylene glycol, and propylene glycol), pre-freezing method(dryice-pellet, dryice-straw and L$N_2$vapour-st-raw) and total time required for freezing(2. 5, and 7 h) were compared as a factors. To investigate quality of semen during freezing process, motility(%), normal apical ridges(%, NAR), and proportion of living sperm(%) by flow cytometic analysis were assessed after collection, cooled, pre-frozen and post-thawing. Post-thaw motility of semen diluted with M-Soejima was 52.0%, respectively. When heparin, caffeine or heparin＋caffeine was added to 2nd cryodiluent of M-Soejima during freezing process, the highest motility after thawing was shown at the addition of caffeine (2mM), with 61.7$\pm$2.9% of motility. M-Soejima with heparin or caffeine was significantly higher than that of controI(p＜0.05). The result using glycerol(Gly), ethylene glycol(EG), propylene glycol(PG), and their mixture (Gly＋EG and Gly＋PG) as cryoprotectants, the highest motility was shown at the mixture treatment with Gly plus PG. However, the highest proportion of live spermatozoa was shown at Gly＋EG, there was no significantly difference among treatments(p＞0.05). When semen was pre-frozen with three manners(dryice-pellet, dryice-straw, and L$N_2$ vapor-straw), motility(%) of post-thaw spermatozoa was the highest in the L$N_2$ vapor-straw pre-freezing method of M-Soejima cryodiluent with 57.5% of motility, For a simple, economical and timesaving approach to freezing boar semen, total time required for freezing were 2, 5, and 7 hours, post-thaw motility were 43.8, 45.0 and 38.8%, NAR were 19.5, 22.7 and 28.5%, and viability were 20.8, 19.9 and 22.1%, respectively. This data suggests that boar semen diluted with M-Soejima cryodiluent contained caffeine, using mixture of glycerol and propylene glycol or ethylene glycol as cryoprotectants, frozen with 2 hours, can be taken better motility, NAR, and proportion of live spermatozoa.

• Korean Journal of Animal Reproduction
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• v.22 no.4
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• pp.307-317
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• 1998

This study was to investigate the vitrification method for cryopreservation technique of bovine in vitro fertilization(IVF) embryos. The morphological appearance and viability following vitrification of IVF bovine blastocysts and expanded blastocysts were examined. Embryos obtained 6, 7, 8 or 9 days after IVF were vitrified in both 40% ethylene glycoI(EG) plus 0.3M trehalose and 20% polyvinylpyrrolidone(PVP) in DPBS(ETP, Exp. 1) and ETP solution added 0.375M dextrose (ETPD, Exp. 2). The viability of Days 6, 7, 8 and 9 vitrified /thawed embryos at 24∼48 h culture after thawing was 11.9%, 19.8%, 23.4% and 15.3% in ETP(Exp. 1), and 34.6%, 54.5%, 37.9% and 13.0% in ETPD(Exp. 2), respectively. The viability of vitrified embryos produced from the culture days after IVF did not differ in Exp. 1, but significantly differ in Exp. 2(P＜0.05). The viability of blastocysts and expanded blastocysts significantly differed(P＜0.05) in 15.2% and 23.3%(Exp. 1), and 25.0% and 45.8%(Exp. 2). The result of Exp. 1 was similar to that of Exp. 2 on the viability of embryo according to developmental stages, but ETP solution plus sugar(dextrose) was increased the viability of vitrified embryos. In Experiment 3, The viability of vitrified embryos was not different between 12% and 20% PVP concentrations in ETP solution according to culture days or developmental stages. To investigate the effect of addition of sugar, two type of carbohydrates and a mixture of cryoprotectants for vitrification on the survival of bovine IVF embryos, bovine Days 7 to 9 blastocysts and expanded blastocysts were cryopreserved in either 20% glycerol plus 20% EG, 0.375M sucrose and 0.375M dextrose (GESD, Exp. 4) or 20% glycerol plus 20% EG, 0.3M trehalose and 20% PVP(GETP, Exp. 5) in DPBS. Survival rates of Day 7, 8 and 9 embryos at 24∼48h culture after thawing were 71.4%, 94.6% and 40.5% in GESD, and 59.5%, 81.5% and 62.5% in GETP, respectively. Hatching rates of Day 7, 8 and 9 embryos after thawing were 28.6%, 35.1% and 16.2% in GESD, and 27.0%, 33.3% and 18.8% in GETP, respectively. These results indicates that a mixture of cryoprotectants(glycerol and EG) and addition of sugar can improve the survival rates of the bovine IVF embryos(Day 7 or 8) vitrified, and the expanded blastocyst embryos are more suitable for vitrification than early blastocysts stage.

• Journal of the Korean Society of Food Culture
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• v.20 no.6
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• pp.738-743
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• 2005

This study was performed to investigate the quality characteristics of pine mushroom yanggaeng prepared with different additions and different preparations of pine mushroom. Yanggaeng was prepared with three concentration of pine mushroom after different preparations of pine mushroom, A hot wind drying 0.1%, 0.3%, 0.5%, Frozen pine mushroom grinding 0.1%, 0.3%, 0.5%, Freezed drying 0.1%, 0.3%, 0.5%, to which was added cooked red bean, agar, oligosaccharide, salt and water. Proximate composition, hunter's color, texture profile analysis and sensory evaluation of yanggaeng were examined. Lightness of pine mushroom yangaeng increased with increasing pine mushroom content and frozen pine mushroom grinding products were higher than those of the preparation products. In the texture profile analysis, hardness of pine mushroom yangaeng increased with increasing pine mushroom content and cohesiveness, springiness of Frozen pine mushroom grinding 0.1% were the highest. In sensory evaluation, the taste and viscosity scores of Freezed drying 0.1% higher than those of the other products. Also the overall acceptability of freezed drying 0.1% pine mushroom yanggaeng was the highest of the all products.

• Journal of Life Science
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• v.30 no.1
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• pp.77-81
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• 2020

The aim of this study was to overcome some of the limiting factors that the maxi cryopreservation straw of 5 ml presents in processing boar semen. Cryopreservation of semen samples was conducted in 0.5 ml and 5.0 ml straws at two freezing rates: -140℃ in 8 minutes and 30 seconds (FR-1) and -140℃ in 14 minutes (FR-2). The straws were then thawed and the semen parameters were compared by Computer Assisted Sperm Analysis, and sperm morphology and acrosome status were examined by Coomassie blue staining. The effects of different thawing temperatures and durations were also compared, namely 37℃ for 115 sec, 50℃ for 45 sec, or 70℃ for 25 sec. In general, the FR-1 group showed higher (p<0.05) sperm viability and motility than the FR-2 group in the 5.0 ml straws. Compared to other ranges, thawing at 50℃ for 45 sec showed the highest sperm viability and motility (68.4±3.6% and 69.5±2.2%, p<0.05), suggesting that thawing temperature should be adjusted concurrently with freezing rate. Sperm morphology and acrosome integrity did not significantly differ among the groups (p>0.05). The data obtained in this study suggest that improving the freezing-thawing protocol for one artificial insemination dose straws (5.0 ml) retains the sperm's parameters from 0.5 ml cryopreservation, and is more convenient to handle, which could result in enhanced reproductive performance.

• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.74-74
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• 2001

난자 동결방법의 선별은 보다 효과적인 난자은행의 개발에 필수 불가결한 중요한 요소이다. 이전의 연구에서 마우스의 난자를 ethylene glycol과 electron microscope grid를 이용한 유리화 동결법으로 동결 융해한 결과 기존의 slow freezing 방법에서보다 높은 생존율과 배발달율이 나타남을 관찰하였다. 그러나 동결융해후의 난자는 방추사와 염색체의 이상성이 대조군에 비해 높은 빈도로 나타나 융해후의 배발달율을 감소시키는 것으로 보고되었다. 이에 본 연구에서는 유리화동결법동안 항동해제에 Cytoskeleton system을 안정화시키는 cytoskeleton stabilizer인 taxol을 첨가시킨후 동결시켰을때 생존율과 발달율을 개선시킬 수 있는지 알아보고자 본 실험을 시행하였다. ICR mouse의 성숙란을 채취하여 연구목적에 따라 taxol을 첨가시키지 않은 대조군과 첨가시킨 실험군으로 분류하였다. 동결방법은 난자를 1.5 M ethylene glycol (EG)에 2분 30초간 노출시킨후 5.5 M EG와 1 M sucrose가 첨가된 동결액에 20초간 노출시킨 후 Grid에 난자를 부착시킨후 직접 액체질소에 침지하여 동결하였다. 동결후 난자는 5단계로 융해를 실시한 후 정자와 체외수정을 시킨 후 수정된 난자는 modified P1 배약액에 124 h까지 발달율을 관찰하였고, 배양 후 발달된 배반포는 대조군과 실험군, 각각 4마리의 발정동기화된 recipient에 이식을 시행하였다. 배발달율은 대조군에 비해 실험군에서 4세포기 (48 vs. 84.4%), 8세포기 (34% vs. 70.6%), 상실배 (26% vs. 58.6%) 그리고 배반포 발달율은 (24% vs. 58.6%)로 높게 관찰되었다. 배아이식후 대조군과 실험군에서 각각 2 마리가 임신이되어 정상적인 산자를 분만하였다. 따라서 항동해제에 taxol의 첨가는 동결 융해후의 난자의 배발달율을 증진시킬 수 있었다..8%로 나타나 난할율 및 배반포 발생율에 있어서 융합조건에 따라 큰 차이는 없었으나 1.9㎸/cm, 30$\mu\textrm{s}$ 2회의 조건이 다른 조건들에 비하여 유의적으로 낮았다. 따라서, 체세포와 수핵란 세포질간의 융합율과 배반포 발생에 미치는 영향은 전압보다는 시간에 더 크게 받음을 알 수 있었으며, 이와 같은 결과에서 융합시 시간을 오래 주는 것보다 전압을 높이는 것이 수핵난자의 세포질에 상해를 줄이고 이후 배반포 발생에 유리할 것으로 사료되었다.면에서도 더욱 더 활발할 것으로 기대된다. 배란후 72시간째에 초음파진단기를 이용하여 난소의 난포발달을 조사한 결과 , 대조구와 bFF처리구에 비해 AI처리구에서 발달난포가 유의적으로 많은 것을 확인하였다. 이상과 같은 결과로, Anti-inhibin serum은 한우 자체에서 분비하는 Inhibin을 특이하게 억제하여 Inhibin에 의해 억제되는 FSH분비가 촉진됨으로써 난포발달과 estrogen의 농도가 촉진되는 것으로 사료되어 anti-inhibin serum이 한우의 과배란유기 효과가 있는 것으로 사료된다.정량 분석한 결과이다. 시편의 조성은 33.6 at% U, 66.4 at% O의 결과를 얻었다. 산화물 핵연료의 표면 관찰 및 정량 분석 시험시 시편 표면을 전도성 물질로 증착시키지 않고, Silver Paint 에 시편을 접착하는 방법으로도 만족한 시험 결과를 얻을 수 있었다.째, 회복기 중에 일어나는 입자들의 유입은 자기폭풍의 지속시간을 연장시키는 경향을 보이며 큰 자기폭풍일수록 현저했다. 주상에서 관측된 이러한 특성은 서브스톰 확장기 활동이 자기폭풍의 발달과 밀접한 관계가 있음을 시사한다.se that were all low in two aspects, named "the Nonsignificant group". And the issues were high risk perception in general setting and

• Development and Reproduction
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• v.2 no.1
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• pp.63-68
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• 1998

This study was done to find optimal cryopreservation medium and method to improve the post-thaw motility of human sperm. Thirty three semaen samples were included in the study. Of these, nineteen Samples showing normal semen profile were frozen using three cryprotectants (TYB, TYB+DTT and KS II)to compare post-thaw motility. Fourteen samples were frozen with vapor freezing and programmable freezing methods to compare post-thaw motility in correlation with freezing method. After 24 hrs of cryostorage , the vials were thawed and the post-thaw sperm motility was assessed by two kinds of computer-aededsperm analysis (CASA; SAIS and Hamilton Thorn). As a result, the post-thaw motility of the KS II group was higher than the TYB or TYB+DTT group in normal semen(34.8%, 28.3% and 23.0%, respectively). In the asthenospermia group, a significantly hither post-thaw motility was observed in the KS II (18.5%) compared to those of TYB or TYB+DTT group (13.6%, 10.0%, respectively). No difference was observed between vapor freezing group and computerized freezing group in normal semen (27.8%, 33.2%, respectively) and semen group showing asthenospermia (12.8%, 12.9%, respectively). In conclusion, our results indicate that KS II medium is reliable for cryopreservation of human sperm and vapor freezing and programmable freezing were equally effective in terms of the recovery of motile spermatozoa.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.3
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• pp.1063-1075
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• 2013

The strength of frozen soils is one of the significant design parameters for the construction in frozen ground. The properties of frozen soils should be investigated to understand the strength of frozen soils. The objective of this study is to figure out the characteristics of elastic waves in frozen soils, which reflect the constituent and physical structure of frozen soils in order to provide fundamental information of those according to the degree of saturation. Freezing cell is manufactured to freeze specimens, which are prepared with the degree of saturation of 10%, 40%, and 100%. Piezo disk elements are used as the compressional wave transducers and Bender elements are used as the shear wave transducers. While the temperature of specimens changes from $20^{\circ}C$ to $-10^{\circ}C$, the velocities, resonant frequencies and amplitudes of the compressional and shear waves are investigated based on the elastic wave signatures. Experimental results reveal that the elastic wave velocities increase as the degree of saturation increases. The variation of resonant frequencies coincide with that of elastic wave velocities. A marked discrepancy in amplitudes of compressional and shear waves are observed at the temperature of $0^{\circ}C$. This study renders the basic information of elastic waves in frozen soils according the degree of saturation.